XML Schemas describe the structure of valid documents and can be exploited for improving both the efficiency and effectiveness of queries on valid documents. XML Schemas, however, may need to be updated to adhere to new requirements and to face changes in the application domain. Starting from a set of schema modification primitives, in this paper we devise an incremental validation approach that allows to efficiently validate documents, known to be valid for the original schema, for an updated schema. Then, we enhance the approach to adapt the documents to the new schema. Experiments prove that our approach increases the performance of standard validation algorithms in this setting and that the cost of the adaptation process is limited